Chapter Corner

Water vs. Electricity: Important Considerations for Safety

Posted in: Safety Corner, March 2014

Water at the right place at the right time sustains life; water at the wrong place and the wrong time can become a nightmare. We need water to survive, but on the other hand, water can be quite dangerous and create unsafe conditions especially where electricity is involved. An important part of any design addresses and manages water. Builders work to ensure water does not intrude into the structure and their fight rages on many fronts; some are as obvious as dealing with rainwater through proper roof structures and a gutter system that removes the rainwater from the structure. Other less obvious fronts include preventing water intrusion from ground springs. Managing the elements of nature is important for safety as water intrusion can cause mold, rust, and other similar types of degradation that also may not be received well by electrical equipment. Mixing water and electrical equipment can have devastating results for safety. It’s worth a probe on this topic to get you and your team in the game and ensure safety is not compromised on your next project.

The combination of water and electricity is commonly associated with electrocution and so the National Electrical Code® (NEC) and other codes and standards work to prevent the loss of life through implementation of many different types of solutions, one of which includes ground fault circuit interrupters (GFCI). But water can take a toll on electrical equipment itself. Whether it be intrusion of massive amounts of water due to storms, floods, or similar events or prolonged exposure of electrical equipment to smaller amounts of water, both can be very dangerous for electrical systems. Minerals and other contaminants can also be found within the water molecules and can present additional concerns even after the water evaporates away. As electrical professionals we need to understand more about this topic of electrical equipment and water and how to deal with the aftermath of a problem that causes these two to meet.

Wet, Damp, and Dry Locations

When applying products it is important to understand in which environment they will be applied. The NEC helps us with this by defining some important terms and referencing these terms when providing installation requirements.

The key terms defined in the NEC include the following:

Location, Damp. Locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture.

Accompanying this definition is an informational note adding more clarification; damp locations may be difficult to spot. The informational note offers examples of damp locations which include partially protected locations under canopies, marquees, roofed open porches, and like locations. Also mentioned are interior locations subject to moderate degrees of moisture, such as some basements, barns, and cold- storage warehouses. Identifying a damp location may not be as black and white as you may think. Many situations present themselves that you may think are dry locations but in fact are damp.

→ Location, Dry. A location not normally subject to dampness or wetness. A location classified as dry may be temporarily subject to dampness or wetness, as in the case of a building under construction.

Location, Wet. Installations underground or in concrete slabs or masonry in direct contact with the earth; in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather.

I have received many questions focused on situations surrounding flooding where electrical equipment was in a flood or water was poured directly through the equipment. The hard questions though surround those less obvious situations such as those where equipment is found with beads of water in and on sensitive areas. Many take it upon themselves to de-energize and dry the equipment after fixing the water intrusion issues. The equipment may appear to be perfectly fine when in reality problems could be hidden. Drops of water may include contaminants that over time degrade the equipment. The degradation may occur well out of eyesight and well after the perpetrator has left the scene.

Identifying the Hazards

Protecting electrical equipment from water damage begins well before installation. Storage of your equipment before installation is just as important. Just because a product that has been sitting in water has never been installed does not mean the water did not perform or start a process that will result in damage. Building codes provide installation requirements that help, but it is advisable to train your eye to think out of the box and observe areas that could be problematic later. Design them out; address them early.

Look for any potential water source from the obvious to the not so obvious. The following should kick start your thought process.

Water pipes. It doesn’t take the presence of a fitting such as an elbow or union or similar to present the hazard to your equipment. A water pipe can be damaged in and around your equipment presenting the hazard. Also, the less obvious but probably more possible issue is when a leak from a distant portion of the pipe finds water following the pipe to where it eventually drips or pours onto electrical equipment.

Windows. Less obvious sources of water may be areas around windows that may become compromised and eventually let rainwater or other sources of water in. Also, windows may be opened and possibly left open.

Activities. Hose down or similar areas can present a problem long after the installation. What occurs in that area where electrical equipment is located may not be as obvious as when you are installing equipment within a car wash. Areas like garages and those in and around farm animals can be locations where hose down occurs. Awareness of the surroundings and purpose of the facilities is important.

Humidity. A much less obvious source of water is presented through the presence of humidity. An example that the NEC has recently addressed includes those areas where conduit travels from outside of the structure to the equipment inside of the structure. Changes in temperature can create condensation, a very harmful long- term condition for electrical equipment.

A word about humidity as this is a topic that could become one of those questionable gray areas. Electrical products have environmental specifications, and humidity is one of those criteria. Percent relative humidity is important and product technical specifications will specify the maximum humidity permitted as well as “noncondensing” environments. Condensation can be a slow killer as not only the water but also the minerals, particles, and contaminants that may be present in the water cause problems over the long term. Equipment instructions and specifications may be very forthright with this important information. For example, molded-case circuit breakers are typically suited for operation in 0 to 95 percent noncondensing humidity environments. Electronic equipment on the other hand may have lower limits. Metering equipment from one manufacturer specifies a 5 to 95 percent noncondensing requirement at 50oC. Other equipment specifies a 10 to 80 percent noncondensing environment. Installing as per manufacturer instructions is important. Requirements for equipment will vary so you have to read and understand what the manufacturer requires.

In some cases, too little humidity can be harmful as well. In environments with very low humidity, static electricity becomes a problem, and in areas with sensitive electronics, this can be devastating. The bottom line in all of this discussion is to follow the manufacturer’s instructions very closely.

Planning and Preparation

All accidents cannot be avoided but planning and preparation can minimize their occurrence or minimize their impact. Codes and standards are a great place to start in your journey, but again, we can’t forget about manufacturer’s instructions. Equipment is available to help protect your electrical equipment. The NEC provides some definitions and examples of steps that can be taken.

Raintight and rainproof equipment are two examples. The NEC defines raintight as, “Constructed or protected so that exposure to a beating rain will not result in the entrance of water under specified test conditions.” Rainproof on the other hand is defined as, “Constructed, protected, or treated so as to prevent rain from interfering with the successful operation of the apparatus under specified test conditions.” There is a subtle but important difference between these two definitions. Another term defined by the NEC is watertight. Watertight equipment is that which is, “Constructed so that moisture will not enter the enclosure under specified test conditions.” The test conditions are a part of the UL standards for the products in question. Always make sure the product fits the application.

The UL standard for enclosures most pertinent to these discussions is UL 50E, “Enclosures for Electrical Equipment, Environmental Considerations,” as it is this standard that establishes the test criteria for the various types of enclosures including Types 1, 2, 3, 3R, 3S, 4, 4X, 5, 6, 6P, 12, 12K, and 13. Each enclosure type provides varying levels of protection to the electrical equipment within. In addition, product standards will include environmental tests that will be found in their respective UL product standards. This all translates into applying the product as per the manufacturer instructions and as per the NEC. The UL White Book provides help as well in understanding the proper application of products. There are various category codes within the White Book but category code BGUZ is a great place to start as it covers “Boxes, Junction and Pull” and includes a good discussion on the enclosure type ratings. Table 110.28 of NEC 2014 helps in the selection and application of enclosures. Outdoor and indoor applications are addressed as are such hazards as hosedown, submersion (both temporary and prolonged), rain, snow, sleet, and splashing when it comes to water and moisture.

The NEC does its part by providing installation guidance such as that included in Section 230.54, “Overhead Service Locations” where in Section 230.54(G) a requirement to ensure water will not enter service raceway or equipment is present. The NEC includes many areas with specific requirements for products installed in dry, wet, and damp locations. Be careful to not modify equipment through drilling of holes or other similar activities as you may void the UL Listing and weather resistant nature of the product being modified. Consult the manufacture before making any field modifications.

When Things Go Wrong

We can plan and design great systems but things can go wrong; water and electrical equipment can and eventually probably will meet. Depending upon the situation, there may be a strong desire or need to energize equipment soon after the event occurs. Electrical equipment that has been exposed to water outside of its rating and listing can be very dangerous. Every precaution should be taken to ensure safe installations. The National Electrical Manufacturers Association (NEMA) has a document to help determine how to evaluate electrical equipment that has been exposed to water through flooding, firefighting activities, hurricanes, etc. This document, “Evaluating Water-Damaged Electrical Equipment,” targets designers, installers, inspectors, and suppliers of electrical products. This is a free reference available from the NEMA web site. To download it, go to http://www.nema. org/Standards/Pages/Evaluating-Water-Damaged-Electrical-Equipment.aspx.

When addressing concerns with electrical equipment that have experienced exposure to water, don’t do it alone; get the manufacturer involved up front to ensure the right decisions are made and the right resources are involved. Some Nationally Recognized Testing Laboratories (NRTL) offer services to evaluate equipment in the field before energizing. Leverage your resources. The last thing you want to happen after surviving a hurricane or similar disaster is to needlessly risk lives energizing water-damaged equipment.

The above is just the tip of the iceberg when it comes to addressing water in and around electrical installations. It should be enough to start your wheels turning and begin to train your eye to prevent and deal with water issues as they arise.

As always, keep safety at the top of your list and ensure you and those around you live to see another day.

Thomas Domitrovich,P.E.,is a National Application Engineer with IEC National Platinum Industry Partner Eaton Corporation in Pittsburgh, Pennsylvania. He has more than 20 years of experience as an Electrical Engineer and is a LEED Accredited Professional. Domitrovich is active in various trade organizations on various levels with IEC, the International Association of Electrical Inspectors, the Institute of Electrical and Electronic Engineers (IEEE), the National Electrical Manufacturer’s Association (NEMA), and the National Fire Protection Association (NFPA). He is involved with and chairs various committees for NEMA and IEEE and is an alternate member on NFPA 73. He is very active in the state-by-state adoption process of NFPA 70, working closely with review committees and other key organizations in this effort.